This invention relates to color television cameras having incorporated therein a color separation system, and more particularly to an optical system for a color television camera, a part of which is operatively combined with an additional light arrangement usuable for automatic adjustment of the camera with respect to, for example, color temperature compensation.
The purpose of initial adjustment of a color television camera of the multi-tube type is, as of importance, to superimpose primary colored patterns in registration with each other, namely, the so-called "registration adjustment", and reproduce correct colors, namely, the so-called "color balance adjustment", and, in application to outdoor photography, to compensate a change in color temperature which may be encountered during operations of the camera where different lighting situations are successively given. Each time the color temperature of the lighting situation is changed, it has been the prior art practice either or both to introduce white light from a temporarily employed white object of reference into the television camera lens with the resulting output signals of the individual pick-up tubes being modulated by gain adjustment to predetermined ratios, in color balance, and/or to insert a filter into the optical path of the photographic objective lens, with the resulting outputs of the tubes being modulated in white balance to compensate the change in color temperature. This necessity of always carrying about the reference object along with the television camera and further of bringing the reference object into and holding in photographing relation to the television camera lens to effect the introduction of white light thereto each time the camera adjustment is made is very inconvenient.